Novel BTK mutation in X-linked agammaglobulinemia: Report of a 17-year-old male

Abstract

Introduction and objectives: X-linked agammaglobulinemia (XLA), the first known primary immunodeficiency, is caused by rare mutations in Bruton’s tyrosine kinase (BTK) gene. Mutations in the BTK gene lead to a failure in the development and maturation of B-cell linage. A decreased number of B-cells results in agammaglobulinemia and increased susceptibility to a variety of infections. Therefore, patients with XLA usually manifest with repetitive bacterial infections, such as upper respiratory tract infections, septic arthritis, osteomyelitis, and urinary tract infections, since their infancy. Patients: We report a 17-year-old Iranian boy with XLA, referred to us with a history of severe and recurrent episodes of bacterial infections for a period of six years. Results: Genetic analysis using the whole Exome sequencing revealed a hemizygous missense mutation in the BTK gene (c.428 A > T, p.His143Leu). Conclusion: To our knowledge, c.428 A > T has not been reported in the BTK gene.